GYMNOSPORANGIUM. 



385 



Experimental infection with teleutospores of GymTWspor- 

 angium clavariaeforme from Juiiiperus communis gave the fol- 

 lowing results : 



On Ho3t-plant. 

 Crataegus Oxyacantha, 

 Pyrm communis, 

 Crataegus tomentosa, 

 Crataegus Oxyacantha, 



„ monogi/na, 



Pyrus communis, 

 Pyrus torminalis, 

 Pyrus Malus, 

 Amelanchier, 



Crataegus Oxyacantha, 



Crataegus grandiflcn-us, 

 sanguinea, 

 „ nigra, 

 Cydonia vulgaris, 

 Pyrus Aucv/paria, 



Pyrus latifolia, 

 Cydonia vulgaris, 



Crataegus nigra, 



Crataegus Douglasii, 

 Pyrus Aria, 

 Pyrus Aucuparia, 



Pyrus communis. 



Authority. 

 Plow right. 



Thaxter. 

 Edthay. 



Spore-form. 



} (?) 



R. lacerata, 



VR. lacerata, 



Roestelia (?), 

 pyonidia, 



)j 

 K. lacerata x, 

 R. lacerata aud aecidia ^ 

 ■with long tube-shaped j-Tubeuf. 



Oersted. 

 Thaxter. 



peridia, 

 R. lacerata. 





little 

 aecidia 



only pycnidia, 

 only pycnidia, 

 Jpycnidia and 

 \ aecidia, 



f pycnidia and aeciaia i 

 - \ with long tube-shaped J-Peyritsoh. 

 [ peridia, J 



Jpycnidia and little ) 

 \ aecidia, 



)j it » 



only leaf -spots, 



no result, 



,' pycnidia and aecidia with 

 ( a long peridium, 



Note. — Before the relationship of the teleutospore-forms was known, the 

 aecidia were designated respectively : Roestelia lacerata on Crataegus, R. comuta 

 on Pyrm Aucuparia, and R. pencillata on Apple. 



The most abundant germination of sporidia takes place on 

 species of Crataegus, and pycnidia (spermogonia) may make 

 their appearance within fourteen days after infection on little 

 yellowish sticky spots on leaves and shoots. By the time conidia 

 (spermatia) have made their appearance, deformation may be 

 far advanced. I did not succeed either in procuring germination 

 of the conidia, or infection by means of them. 



2b 



